Instantaneous trip circuit breaker



March30, 1954 J. c. BRUMFIELD 2,673,908

INSTANTANEOUS TRIP CIRCUIT BREAKER Filed Dec. 29, 1951 3 Sheets-Sheet l 1 4/c L /c 54 .6;

IN VEN TOR.

M va -M March 30, 1954 Filed Dec. 29, 1951 J. C. BRUMFIELD INSTANTANEOUS TRIP CIRCUIT BREAKER Sheets-Sheet 2 $5.55 Ira/1 NVENTOR.

. Jeanne-4o @MQ M ATMKA/EYS March 30, 1954 Filed Dec. 29, 1951 J. C. BRUMFIELD INSTANTANEOUS TRIP CIRCUIT BREAKER 3 Sheets-Sheet 3 INVENTOR.

Jaw/v 4' liar/Illa UN [T E D STATE S Patented Mar. 30, 1954 I INSTANTANEOUS' TRIP CIRCUIT BREAKER John C. Brumfield', Philadelphia, Pa., :assignor. to I-T-E Circuit Breaker Company, Philadelphia,

PATENT OFFICE Pa., a-corporation of Pennsylvania Application December 29, 1951, Serial No. 264,097

signed forfeeder and branch circuit protection are usually provided with thermally operated devices for-use in load centers, lighting and distribution panel boards, convertible power panels on switchboards or in individual enclosures.

These-types of circuit breakers are used for overload protection of insulator conductors. This protection is usuallyrequired in a system at points where wire size is reduced.

In better type circuit breakers a magnetic tripping device is added to the thermally responsive member so that the thermally responsive member isoperativeto open the circuit breaker for values of fault currents below a certain-maximum value, Whilethe magnetic means becomes operative for any valueof fault current above that maximum value.

. In this way the magnetic member will protect the thermally responsive member from very large currents that might permanently injure the metal of which 'thethermally responsive member is made. Since these circuit-breakers have to perform so many functions, they must be small in size and extremely compact, and "all their component partsmust occupy the smallest possible amount of space.

Furthermore, the magnetic tripping device must be regulated sothat itwill reallyprotect the I thermally responsive member from'damage. V In .other words, the movable member of the magnetic tripping device must be of such construction that when a large fault current flows in the circuit breaker the movable element will immediately respond to"thatcurrent and trip the circuit "breaker open.

jWhen-thecircuit breakers are multi-pole circuit breakers, a further problem is added in that inorder to 'protectthe circuits from single phasing, that is, in order to avoid having two circuits closed while the other one has been opened bea tripper bar operable by the armature of the magnetic tripping device, the tripperbar-being also operableby the thermally responsive means.

The movable armature is so constructed that r easy regulation isachieved for tripping the circuit breaker with a magnetic tripping device when the fault currents magnitude is above a certain minimum value.

In the two and three pole embodiment of my all three poles of the circuit breaker and every pole of the circuitbreaker is further provided with-individual and independently operated thermally responsive means in any one of the lines protected by the circuit breaker and therefore willproduce instantaneous and immediate opening of all three poles'of the circuitbreakenthus avoiding single'phasing. Y

lWOre specifically, thetripper bar in my invention is provided with three extensions, if the circuit breakerunder consideration is a three-pole circuit breaker,- perpendicular to the axis of the tripper baritself.

Each of these extensions is provided at one end with a hole engageable'by thehook-shaped end of the armature of a magnet, the other side of the armature being secured to the same support on which the magnet is mounted.

In the example of the three-pole circuit breaker, the tripper bar is also so shaped at the center or main-pole that when the tripper bar is rotated it permits the latch to release the cradle of the circuit breaker, thus-opening the circuit breaker.

As previously mentioned, the tripper barhas three extensions for a three-pole circuit breaker. Each of these extensions is provided. at one end with a hole to be engaged by the hook-shaped end of the armature of the fault current responsive magnet.

-The other end of these extensions of the tripper bar is so prolonged that it may be hit by the free end 'of the thermally responsive means on which is mounted the magnet and which is supported by the same member that supports the armature of the magnet.

If the fault current fiowing through the circuit breaker is below a certain magnitude, the thermally; responsive means will become operative, will bendand will cause the tripper bar to rotate in one'direction to unlatch the cradle and to open the circuit breaker.

-'When, on'the other hand, the fault current flowing through the circuit breaker is greater than the above-mentioned value, the magnet becomes operative before the thermally responsive means can be damaged and it attracts to itself the armature which being hooked to the tripper bar causes the tripper bar to rotate in the same direction as previously mentioned to unlatch the cradle and, therefore, open the circuit breaker.

If it is desired to change the value of the current at which the magnet becomes operative, it is only necessary to move its armature nearer to the magnet or at least to move its armature in such a position with respect to the magnet that a smaller amount of magnetic pull is required to operate the tripper bar connected to the armature.

The main object of my present invention is the provision of means whereby the fault current responsive means are simplified and made more economicalto produce.

Another object of my present invention is the provision of a hook-shaped armature continuously engaging a tripper bar.

A further object of my present invention is the provision of a tripper bar so shaped that it can be operated both by thermally responsive means and magnetic means to trip the circuit breaker open.

Another object of my present invention is the provision of means whereby the value of current at which the magnetic fault current responsive means become operative is easily changed.

A further object of my present invention is a novel latch surface, an integral part of a tripper bar.

The foregoing and many other objects of my invention will become apparent in the following description and drawings in which:

Figure 1a is a top view with the cover removed of a circuit breaker incorporating my present invention.

Figure 1b is a sectional view of the circuit breaker of Figure 1a taken on line bb of Figure la looking in the direction of the arrows.

Figure 1c is another sectional view of the circuit breaker of Figure 1a taken on line cc of Figure la and looking in the direction of the arrows.

Figure 2a is a detail drawing of my novel armature and tripper bar showing the armature before its operation under fault currents.

Figure 2b is a detail drawing of my novel armature and tripper bar showing the armature at the instant of operation under fault currents.

Figure 3a is a detail drawing of my novel latching means.

Figure 3b is a detail drawing of my novel latching surface.

Figure 3c is the front view of the latching surface of Figure 312.

Figure 4 is another sectional view of the circuit breaker incorporating my invention showing the circuit breaker in the closed position.

Figure 5 is another sectional view of the circuit breaker incorporating my invention showing the circuit breaker in the tripped open position.

Referring first to Figures 1a, 1b, and showing the three-pole embodiment of my present invention, the housing of circuit breaker l0, preferably made of a plastic substance, is provided with appropriate openings 2| and 22 through which the circuit breaker terminals 25 and 26, respectively, are substantially brought out of housing 29 to be engaged by the line terminals (not shown) of the line to be protected.

Housing 20 consists of two sections, a base 20a which is the section of housing 20 on which the different elements of circiut breaker III are mounted as hereinafter described and a cover 20?) which completely closes circuit breaker ID by engaging tightly base 2011.

Since a three-pole circuit breaker I0 is being considered in this example, it is quite evident that there will be three sets of circuit breaker terminals 25 and 26, but to make this description clearer the center phase B of the three-pole circuit breaker in having phases A, B and C will be described first.

Considering then this center phase B of the three-pole circuit breaker ID, the circuit breaker terminal 253 rests against an extending shoulder 28B of molding 20a. Shoulder 28B is cenr trally perforated at 2913 to house eventually a bolt and a nut (not shown) to secure the line terminal (not shown) to circuit breaker terminal 253. As previously mentioned, circuit breaker terminal 253 extends through opening 2IB into base 28a. Circuit breaker terminal 258 is shaped like an angle, one side 39B of the angle being used to receive a line terminal (not shown), while the other side BIB is soldered or in any other way connected to a pigtail or conductor B.

Pigtail 35B is rigidly secured to the free end 3113 of thermally responsive member 38B (Figure 2a). Free end 313 is provided with a bolt 40B and a nut MB. Extension 43B of bolt 40B serves a purpose hereinafter set forth.

Thermally responsive means 383 is secured at its other end to a metallic angle 453 through a rivet 4GB or any other suitable means. Angle 45B is secured to housing 20 through a screw MB. A metallic member 48B is interposed between the angle 45B and the surface of the housing 20. Metallic member 48B is connected to a second pigtail or conductor 52B. Washer 53B is interposed between the head of screw 41B and the angle 45B.

Rivet 463 which serves to secure thermally responsive means 38B to angle 453 also serves to secure substantially rectangularly shaped magnet 5013 to thermally responsive means 383.

The armature 55B for magnet B is hookshaped and is loosely pivoted at its end 563 between the head of screw 41B and the head of the rivet 46B. The hook B of armature 5513 engages a hole 5813 in one extension 603 of tripper bar 65.

Tripper bar 65 is provided at this phase B and in all other phases A and C with two members and 66 extending in opposite directions with respect to each other and in a plane perpendicular to the axis of rotation of tripper bar 65.

Considering the center phase B, although this will be true also for phases A and 0, member 663 extends opposite to extension 633 of screw 4013.

In Figures 1b and 1c the circuit breaker i0 is shown in the open position but not after being tripped by fault currents. The tripping mechanism will retain all the relative positions shown in the above-mentioned figure also when the circuit breaker I0 is closed, the relative position changing only if fault currents flow through any phase of the circuit breaker Ill.

In the above-mentioned figure, extensions 69B and 66B of tripper bar are essentially parallel to the thermally responsive means 38B while armature 55B of the magnetic responsive means 508 is at an angle (acute) with respect to the same thermally responsive means 383 and, therefore, of magnet 5GB.

When under fault current conditions the thermally responsive means 383 becomes operative, it will bend and will impart to extension 66B of .cuit breaker through tripper bar 65an-iinpactthrough extension 433 of screw 403.

Iffon the other hand, magnet B becomes 7' operative, it will pull toward itself armature B which being hooked into extension 6913 of tripper bar will impart to tripper bar 65a rotation which as shown; in this drawin will be counterclockwise (see Figures 2a and 211.)

It is easily seen, of course, that when extension 43B of screw UB hits extension 66B of trip-' per bar fiii it will impart to tripper bar 65 a motion which as shown in the figure will be 001111- terclockwise.

1 In ;other words, both thermally responsive means 383 and magnet 5013 when operative will impart to tripper bar 65 a motion that is counterclockwise.

The value of fault current at which thermally responsive means 383 hits tripper bar 65 is rogu ,lated by means of screi'a 403. In fact, ifscrew extension 433 is near extension 65B oftripper 1 bar 65-, the value of fault current at which the thermally responsive means 3813 becomes operative will be relatively small, the opposite being true if screw extension 433 is moved awayfro'm extension 663. r The value of current at which magnet 5333 I becomes operative and pulls armature 55B coma pletely toward magnet 5813 can also be regulatedv by increasing or decreasing the angle formedfby armature 553 with respect to magnet50B. "It is evident, of course that when the angle is increased or the armature 55B is moved away from magnet 5313 the value of current at which arma-W ture 55B is pulled to magnet 59B is greater than .when the angle. i decreased or the armature 55B is moved nearer'to magnet 50B. 1

Referring to Fi-ures 1a, 1b and 1c,'pigtail 213 I from fault current responsive means 383 and fiiiBis electrically connected in any Suitable way to one end 1GB of movab'e contact arm 51B. Movable contact arm "FIB is pivotedby means jof pivot pin 12B engaging aligned openings (3Bof the metallic frame or support .153.

Contact arm m3 is provided at its other-.ehd with a substantially rectangular shaped contact slab 1713. Contact slab 31B. madeofgood conducting material is rigidly secured tocontact arm l IB by means of a rivet 18B or'in any other suitable way.

Stationary contact 3M3 consistsof a rectangular section. metallic member 8113 having at the 1 end nearer to contact arrn'IIB astationary con- Qtactslab rigidly secured toumember 8, I B,., Member MB is secured to housin as of the cir-" a screw 85B and; a Washer 813.

line terminal to circuit breaker terminal 25. M

Stationary contact 863 is also provided with an, arc extinguishing chamber tcB or arc chute h aV ing a number of arc extinguishing plates Sol-a so that at the opening portion of the circuit breaker the arc existing between contactv slab ,TIB contact slab 85B is extinguished before producing damage to the contact slabs 'ilB and 8513.

Contact arm HE is provided nearits center with another set of aligned openings 513% which are engaged by a pin IQI B carrying two metallic fingers IU3B which are one member of "circuit breaker toggle mechanism I05 B. The two finger a members I933 which are secured to contact arm I'IB by means of pin IIJI B are, therefore, rotatable with respect to contact arm HE and an upward or downward motion of fingers I033 will be accompanied by a rotation of contact arm 'IIB around'its pivot 52B. The two fingers I03B are rigidly secured by means of a rivet IBGB located approximately centrally in fingers "13B.

At the other end of fingers I03B, fingers I033 are provided with aligned openings IGFB which are engaged by another pin IBBB. Between the two fingers 23313 are located the other two members I it? or toggle mechanism I053. These two members Hill? are provided with aligned openings' to be engaged by pin ID8B interiorly with respect to fingers 33B. Between the two members iIllB is located a disc HEB for permitting easy rotation or movement of members I IEPB with respect to members 56333 and vice versa.

Pin 5MB is provided at its two ends I 153 with recesses 5 ME on each of which is secured a spring 158B. Springs 5 iiiB are secured at the other end 1 T-shaped member to a T-shaped member 523B, in its upper portion I223. where springs II 33 engage appropriate openings i233 in that upper portion IZZB of I208. T-shaped member 5 l 293 has two legs IZEB, one on each side of toggle SE53. Legs 2253 are provided with. rivets IZIB which engage U-shaped recesses IZBB, one on each side of frame 15B. shaped that Rivets IZ'IB are so they permit free rotation of j T-shaped member IiiilB with respect to frame T-shaped member IZUB is provided at its upper portion 5228 with an extension I3IB substan- 1 tially rectangular whose use will be described hereinafter.

Upper portion I223 of T-shaped member 5263 is slotted in its mid portion and provided with raised members I323 cut out from 1 the upper portion 223 of T-shaped member IZQB which serves to be engaged by a plastic f] operating handle I353 for manually openin and closing the circuit breaker as hereinafter described.

The upper portion of arms II 0B is also provided with aligned openings I 3113 engaged by rivet I38B which secures the two arms HUB together and engages an opening MOB aligned with openings IiiiB.

Opening 1MB is man essentially V-shaped member or cradle M53. One leg I553 of V- 1 shaped cradle {45B is shaped as shown in Figure 1b to engage a latch M'ZB. Latch MIB. (Figure 3a) is provided with a slot M83 engaged by pin I593 around which latch I 47B can rotate and I, can also have translational motion. I; l Latch M113 is provided with a pointed end i 5IB [latched under normal conditions by a latch sur- (see Figure 3b) is composed of a thin strip of face .55216 on tripper bar 65. Latch surface I523 springmaterial formed with the grain in essenj tially C shape so that it can be snapped or sprung about the member, in this case tripper bar .65,

supporting the latch EEEB. The other leg .I i'IB "of Vrshaped member H5513 is provided with a cylindrical hole (not shown) engaged by a pivot Ipin itiiB secured to the raised portion 35B of framell'EB. Leg 15733 of V-shapedn1ember M513 is provided at the bottom of the V with a shoulder extension 5553. Raised portion i653 of frame 753 is provided with an opening (not shown) through which passes contact slab 17B of movablecontact arm MB and provides a stop for V-shaped cradle I45B.

Near the end 10B of movable contact arm 1 IB at which pigtail 52B is connected, an essentially rectangular section bar I80 is rigidly secured to movable contact arm MB in any suitable way. Shaft or tie bar I80 is common to all three phases A, B and C of the three-pole circuit breaker, being rigidly secured to the ends I of the movable contact arm II of every phase so that if one mov able contact, for example, HE is moved either open or closed, the other two movable contact arms HA and HG will simultaneously perform the same movements.

The circuit breaker I0 is also provided around arc chute 95B with an insulation I853 for completely insulating arc chute 95B.

Referring now to Figures 112 and 4 showing, respectively, the circuit breaker in the open po sition and the circuit breaker in the closed position, when the circuit breaker is in the open position but ready to be closed or, in other words, not open because of fault currents, latch surface I52B of tripper bar 55 engages the pointed end IIB of latch HIIB so that extension I55B of V-shaped cradle M53 is latched at protrusion I8IB of latch member I41B.

Cradle I45B will then be as shown in the two figures and, therefore, remains in that position also when the circuit breaker I0 is manually closed by moving handle I35B from left to right as shown in Figures 112 and 4.

When handle 1353 is moved from left to right, it moves with it T-shaped member I20B which will rotate around pivot I2'IB and at an initial time will tension springs IIBB of toggle 0513. When spring II8B now under tension is moved through T-shaped member I20B over center with respect to toggle I05B, a force is produced by springs II8B which makes toggle as shown in Figure 4 from its collapsed position shown in Figure lb.

When springs IIBB go over center under the continuous motion from left to right of T- shaped member I203, they also bias T-shaped member I20B in a counterclockwise direction of rotation so that T-shaped member I20B will now move clockwise.

In order to stop the clockwise motion of T- shaped member I20B, raised extension I05B of frame 153 is so shaped that legs I253 will hit the two sides of raised extension "553 of frame 153 after T-shaped section I203 is rotated through the correct number of degrees.

As toggle I05 is being made during the motion of T-shaped member I20B from left to right, arms I033 of toggle I05B push movable contact arm HE and cause it to rotate. around its pivot 12B also in a clockwise motion.

When toggle I05B is finally made, contact slab 11B is now under high pressure engagement with stationary contact slab 8513 so that an electrical circuit is now closed between terminal 253 and terminal 26 of circuit breaker I0.

When it is desired to open the circuit breaker I0, handle I35B is moved from right to left as shown in Figures 4 and 1b.

After springs II8B have moved over center through motion of T-shaped member I20B rigid- 1y movable with handle I35B, toggle I05B collapses and causes movable contact MB to rotate around its pivot 1213, thus opening the electrical contact between movable contact slab 11B and stationary contact slab 85B of stationary assembly 80B.

As previously mentioned, during the opening operation an arc will occur between movable slab 11B and stationary slab 85B, but circuit breaker I0 is provided with arc chute 953 which essentially extinguishes the are between slab 11B and slab 853 during the opening operation of circuit breaker I0.

Rotation of movable contact member 'IIB around its pivot 12B is accompanied by similar rotations of the other two movable contact members 1 IA and I I0 of the other two phases A and C, respectively, since the three phases are tied together through tie bar I connected at one extremity I0 of movable contact arms I I.

During both the opening and closing operations of the circuit breaker I0, cradle I453 does not move. In other words, its extension I55B remains in engagement with latch Il'IB which engages latch surface I52B, an integral part of tripper bar 65.

Considering now circuit breaker II! in its closed position and assuming that a fault current occurs in phase B if the fault current is below a certain maximum value, thermally responsive means 38B will bend toward extension 663 of tripper bar 65 and the extension 43B bearing against extension 68B of tripper bar 65 will cause tripper bar 65 to rotate counterclockwise for the drawing shown in Figure 2a.

Counterclockwise rotation of tripper bar causes a similar rotation of the latching surface member I523 mounted on tripper bar 65 in the same direction.

Since latching surface member I52B is shaped essentially circularly with approximately a circular section removed from the circle, counterclockwise rotation of latching surface I52B causes extension I5IB of latch I4'IB to fall into a 90 recess 200. As extension I5IB of latch I4'IB falls into recess 200 of latching surface I52B, latch I IlB rotates and moves with respect to its pivot I50B, thus freeing leg I55B of cradle I45B from engagement with protrusion I8'IB of latch I41. Cradle M513 is thus made free to rotate in a clockwise direction as shown in Figure 5.

As cradle I45B rotates, it moves toggle I05B and with it springs IIBB over center so that springs I I813 now break toggle I053 and as previously described open the circuit breaker electrical contact between contact slab 11B and contact slab 85B. Because of the biasing actions of springs II8B, extension I5IB of cradle I45B will hit raised extension I65B of support 1513 and will be stopped by raised extension I65B.

Also, because of the biasing action of springs IIBB, T-shaped member I20B and with it handle I35B will rotate during this opening operation of circuit breaker I0 from the position shown in Figure 4 to the position shown in Figure 5, the handle being, therefore, now essentially in a mid position between that shown in Figure lb and in Figure 4, allowing the operator to see which electric'al circuit has had a fault.

Of course, as previously mentioned, if the fault occurs in phase B also the other phases A and C will open since the movable contact arms II of the three phases A, B and C are tied together by means of tie bar I80 secured to the ends 10 of movable contact arms II.

If the fault in the line protected by circuit breaker I0 has been repaired or it is cleared, the operator can close circuit breaker I0 from its tripped position as shown in Figure 5. In order to close circuit breaker I0, the operator will first move handle I35B leftwardly as shown in Figure 5 carrying with it cradle I453 since now shoulder extension IGBB of cradle I453 bears against ex- 9 3 tension I3IB of T-shaped member an member lB'rotates with handle-135B;

When' handle"lB-isbrouglitall-the way t of tripper bar 65 1 I After engagement of cradle c p I413, the operator moves handle A3Bfrom-left to'rightnthus closing aliihr B mm 20 of circuit breaker It as previously" explained. -'If-th'e fault should occur in -any of the'other 1453 Withlatch two phases'Aand o andits faultcurrent shou d" be less than a certain maximum, their thrmally' responsive members 38A and 38C,-respect1vely,-

will come into operation; will cause tripper bar 65 to rotate in a counterclockwise direction to release cradle M5B-and performthe-above-de scribed operation, I thus 1 opening all "three phases A,B and C of circuit breaker-l0. v

Ifthefaultcurrent is greater than the abovementioned 7 maximum value, the correspondmg magnet 5t comes into operation before thermally responsive'oneans 38 and attracts armatureiii? toward itself, thus also causing tripper bar- 8E5 to rotate in a counterclockwisedirection and to repeat the above describedoperations withthe resultant opening of phasesm B andfC'of circuit breaker l0; I

Of course, after this opening operation, armature 55 is not any more attracted to magnet and will, therefore, return to its original position in which its extension EGbears'aga-inst molding 20 of circuit breaker it, thus allowing'spring 20! to impart a clockwiserotationofjti'ipperbar f making now possible the *reclosing' operation of circuit breaker IE3.

It is quite evident that a two-pole circuit break or using the same fault current responsive means can be constructed in a manner *siinilarto "the one described in connection with thethreefpole circuit breaker with, of course, one of the phases A "or C missing.

The two-pole circuit breaker may consist of I phase A and phase B'or phase Bandfphalse'C; as "described in connection with a three=pole "CIT-T cuit breaker. In that case also tie bar con necting movable contact arms}! will extendonly between the two-phases of the "two-poleicircuit breaker, thus tying the two movazhl-e" contact arms H of the twoepol'e circuit breaker together.

If a single pole circuit breaker is to be'constructed' using the above described invention, it is only necessary to removephases A and C of the three-pole circuit breaker i0, It of course, evident that in the single pole case no tiebar so will be'necessary, and the tripper bar E5 will be provided with only one set of extensions fillBan'd B6B and one latching surface i523."

The operation of both the "ftwo-pole circuit v breaker and the single pole circuit breakerwill essentially be the same as theone described above inconnection with the three-pole circuit'brea'ker;

the on1y difference being that in the two -p'ol' circuit breaker; for exa ple; only 'the center phaseBef thethree-pole circuit'breaker and one plementary contact, said .ed for rotation around one of the side phases is used'while in thesingle pole circuit breaker only the center phase itself is.

used,

It is also seen that'th'e molding offthe two pole andsingle pole circuit breaker will be differ ent from athree-pole circuit" breaker casing, but since the'variations noted are'quite evident, these modifications will-not'b'e described here. i

In the foregoing I have described my'invention solely in connection with specific illustrative embodi'ments thereof; modifications ofmy i tothose skilled in t not by the specific but only by the I cla'imz I 1. In a circuit breaker f Since many" variations land heart, 'I'prefer to be bound appended claims.

or instantaneous trip opening under fault'current conditions, .a movvable contact, a com able contact arm, a mo movable contact mounttact arm, said movable mplementary contact. at

ed on said movable con contact engaging'sa'id co the circuit-breaker close being disengaged at the contact arm, said tog v gle being collapsed in one direction at the circ uit' breaker closed position and in the opposite direction in the circuit -shaped cradle mount-- of its ends, said toggle-= breaker open position, a V

means being mounted at its other side on the apex of said V-shaped' cradle, a T-shaped member and a handle movable around'itheend of ,the' centralleg of the said T-shaped member, spring means mounted between said and said T-shaped member for bi prising a latch pivoted at its center and a substantially circularlatching surface, a tripper bar rotatable around its axis, said latching surface being mounted on said tripper'bar, said tripperbar also having radial extensions,. thermal1y; responsive and magneti latching means 'tounlatch saidcradle at fault currents, said magnetic means comprising .a-=

magnet and'a movable armature, -.said-magnet being mounted on s'ai said tripper bar extensions. H e I 2. In a circuit breaker for instantaneous trip opening under fault current conditions,--a imove ablecontact arm, a movable contact, a com-- plementary contact; said movable contact arm carrying said movable contact, said movable contact engaging said complementary contact at-the circuit breaker closed position, said contacts being disengaged at the circuit breaker open position, fault current .1'esp0nsive :means -,for

opening said circuit breaker under fault current conditions, said fault current responsive means comprising thermal and magnetiomeansysaidma netic means comprising a hook-shaped ar-: mature and a magnet, said magnet-beingsecured to saidthermally responsive means; saidarmature being pivot'allymovable when attracted by said magnet under fault current (conditions,- saidsaidthermal means to. effect opening of hook-shaped armature andmoved in opposite directions said circuitbreaker under faultcurrent condi; tions: i

'3. In a circuit breaker for instantaneous trip opening under fault current.- conditions, a mov able contact ann; a movable. contact, I a compl'ementary "contact; said'movablecdritact senvention will now be obvious disclosures herein. contained 7 d position, said contacts I circuit breaker open pos-i- -t1on, -toggle-means connected to said'movable movable contact asing: said toggle:- n the collapsedpositionslatchihg means comc means for operatingsaid" 7 d thermally responsive means, said armature comprising a hook-shaped member pivoted at one end and engaging one-of.

cured to said movable contact arm, said movable contact engaging said complementary contact at the circuit breaker closed position, said contacts being disengaged at the circuit breaker open position, fault current responsive means for opening said circuit breaker under fault current conditions, said fault current responsive means comprising thermal and magnetic means, said magnetic means comprising a hook-shaped armature and a magnet, said magnet being secured to said thermally responsive means, said armature being pivotally movable when attracted by said magnet under fault current conditions, a housing comprising a base and a cover, said circuit breaker being mounted on said base, said cover in combination with said base completely covering and protecting said circuit breaker, said hook-shaped armature and said thermal means moved in opposite directions to effect opening of said circuit breaker under fault current conditions.

4. In a multi-pole circuit breaker for instantaneous trip opening under fault current conditions, a plurality of movable contact arms, a plurality of movable contactst, a plurality of complementary contacts, a shaft securing said movable contact arms together for simultaneous movement, said movable contacts mounted on said movable contact arms, said movable contacts engaging said complementary contacts at the circuit breaker closed position, said contacts being disengaged at the circuit breaker open position, a toggle means connected to one of said movable contact arms, said toggle being collapsed in one direction at the circuit breaker closed position and in the opposite direction at the circuit breaker open position, a V-shaped cradle mounted for rotation around one of its ends at the phase of the multi-pole circuit breaker at which the said toggle is located, said toggle means being mounted on its other side on the apex of said V-shaped cradle, a T-shaped member and an insulating handle movable together around the end of the central leg of the said T-shaped member, biasing means mounted between said movable contact and said T-shaped member for biasing said toggle in its collapsed positions, latching means comprising a latch pivoted at its center and a substantially circular latching surface, a tripper bar rotatable around its axis and common to all three poles of the multi-pole circuit breaker, said latching surface being mounted on said tripper bar in correspondence to the said cradle, said tripper bar having a plurality of radial extensions, a plurality of ther mally responsive and magnetic means for rotating said tripper bar and for operating said latching means to unlatch said cradle at fault currents and cause the simultaneous opening of all phases of the multi-pole circuit breaker, each of said magnetic means comprising a magnet and a movable armature, each of said magnets being mounted on one of said thermally responsive means, each of said armatures comprising a hookshaped member pivoted at one end and each engaging one of said tripper bar extensions.

5. In a multi-pole circuit breaker for instantaneous trip opening under fault current conditions, a plurality of movable contact arms, a plurality of movable contacts, a plurality of complementary contacts, a shaft securing said movable contact arms together for simultaneous movement, said movable contacts mounted .on said movable contact arms, said movable con-- tacts engaging said complementary contacts at the circuit breaker closed position, said contacts being disengaged at the circuit breaker open position, a toggle means connected to one of said movable contact arms, said toggle being collapsed in one direction at the circuit breaker closed position and in the opposite direction at the circuit breaker open position, a V-shaped cradle mounted for rotation around one of its ends at the phase of the multi-pole circuit breaker at which the said toggle is located, said toggle means being mounted on its other side on the apex of said V-shaped cradle, a T-shaped member and an insulating handle movable together around the end of the central leg of the said T-shaped member, biasing means mounted between said movable contact and said T-shaped member for biasing said toggle in its collapsed positions, latching means comprising a latch pivoted at its center and a substantially circular latching surface, a tripper bar rotatable around its axis and common to all three poles of the multi-pole circuit breaker, said latching surface being mounted on said tripper bar in correspondence to the said cradle, said tripper bar having a plurality of radial extensions, a plurality of thermally responsive and magnetic means for rotating said tripper bar and for operating said latching means to unlatch said cradle at fault currents and cause the simultaneous opening of all phases of the multi-pole circuit breaker, each of said magnetic means comprising a magnet and a movable armature, each of said magnets being mounted on one of said thermally responsive means, each of said armatures comprising a hook-shaped member pivoted at one end and each engaging one of said tripper bar extensions,

a housing comprising a base and a cover, said multi-pole circuit breaker being completely mounted on said base, said cover being in combination with said base, completely encircling and protecting said multi-pole circuit breaker.

6. In a circuit breaker for instantaneous trip opening under fault current conditions, a movable contact arm, a movable contact, a complementary contact, said movable contact mounted on said movable contact arm, said movable contact engaging said complementary contact at the circuit breaker closed position, said contacts being disengaged at the circuit breaker open position, toggle means connected to said movable contact arm, said toggle being collapsed in one direction at the circuit breaker closed position and in the opposite direction in the circuit breaker open position, a V-shaped cradle mounted for rotation around one of its ends, said toggle means being mounted at its other side on the apex of said V-shaped cradle, a T-shaped member and a handle movable around the end of the central leg of the said T-shaped member, spring means mounted between said movable contact and said T-shaped member for biasing said toggle in the collapsed positions, latching means comprising a latch pivoted at its center and a substantially circular latching surface; said latching surface comprising a thin strip of spring material formed with the grain in essentially cshape, such latching surface forming an economical, easily mounted and smooth latching surface having a minimum of friction, a tripper bar rotatable around its axis, said latching surface being mounted von said tripper bar, said tripper bar also having radial extensions, thermally responsive and magnetic means for operating said latching means to unlatch said cradle at fault currents, said magnetic means comprising 13 a magnet and a movable armature, said magnet being mounted on said thermally responsive means, said armature comprising a hook-shaped member pivoted at one end and engaging one of said tripper bar extensions.

'7. In a multi-pole circuit breaker for instantaneous trip opening under fault current conditions, a plurality of movable contact arms, a plurality of movable contacts, a plurality of complementary contacts, a shaft securing said movable contact arms together for simultaneous movement, said movable contacts mounted on said movable contacts arms, said movable contacts engaging said complementary contacts at the circuit breaker closed position, said contacts being disengaged at the circuit breaker open position, a toggle mean connected. to one of said movable contact arms, said toggle being collapsed in one direction at the circuit breaker closed position and in the opposite direction at the circuit breaker open position, a V-shaped cradle mounted for rotation around one of its ends at the phase of the multi-pole circuit breaker at which the said toggle is located, said toggle means being mounted on its other side on the apex of said V-shaped cradle, a T-shaped member and an insulating handle movable together around the end of the central leg of the said T-shaped member, biasing means mounted between said movable contact and said T-shaped member for biasing said toggle in its collapsed positions, latching means comprising a latch pivoted at its center and a substantially circular latching surface; said latching surface comprising a thin strip of spring material formed with the grain in essentially G shape, such latching surface forming an economical, easily mounted and smoth latching surface having a minimum of friction, a tripper bar rotatable around its axis and common to all three poles of the multi-pole circuit breaker, said latching surface being mounted on said tripper bar in correspondence to the said cradle, said tripper bar having a plurality of radial extensions, a plurality of thermally responsive and magnetic means for rotating said tripper bar and for operating said latching means to unlatch said cradle at fault currents and cause the simultaneous opening of all phases of the multi-pole circuit breaker, each of said magnetic means comprising a magnet and a movable armature, each of said magnets being mounted on one of said thermally responsive means, each of said armatures comprising a hook-shaped member pivoted at one end and each engaging one of said tripper bar extensions.

8. In a circuit breaker for instantaneous trip opening under fault current conditions, a movable contact arm, a tripper bar, a movable contact, a complementary contact; said movable contact arm carrying said movable contact; said movable contact engaging said complementary contact at the circuit breaker clo ed position; said contact being disengaged at the circuit breaker open position; fault current responsive means for opening said circuit breaker under fault current conditions; said fault current responsive means comprising thermal and magnetic means; said magnetic means comprising a magnet and a hookshaped armature; said hook-shaped armature being pivotally mounted to said circuit breaker for rotation about its end; said magnet attracting said armature during the occurrence of fault current conditions; said hook-shaped armature engaging said tripper bar; said hook-shaped armature producing rotation of said tripper bar when attracted by said magnet.

J OHN C. BRUMFTELD.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,588,497 Dorfman et al Mar. 11, 1952 2,590,663 Walker Mar. 25, 1952 

